Improvement in adjustable try-squares



UNITED STATES PATENT OFFICE.

CHARLES'A. SCHAEFER, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN `ADJUSTABLE TRV-SQUARES.

Specification forming part of Letters Patent No. 139,821, dated J une l0, 1873; application tiled April 12, 1873.

' Improvement in Squares; and I do hereby declare -the` following to be a full, clear, and exact description of the same, reference being `had to the accompanying drawings, in which- Figuresl and 2 are elevations of squares showing my improvement; .the latter igure beingpartly in section. Fig. 3 is an elevation of one of the adjusting-screws, such as I prefer to employ.

This invention Vrelates to that class of implements known as squares, used by artisans in wood and meta-l. These squares have hitherto been made with the blade set rigidly in the stock, and their whole value consists in the accuracy of the manufacturer, and it is not only well known as a fact, but must appear evident, that in practice, it will be diicult to obtain the desired truth of settin g. It appears also to be evident that accident may destroy the truth of a square which originally was accurate, and when once so destroyed it will be practically impossible for an ordinary workxnan to reset it. The object of my improvement is to correct this defect by making the blade of a try-square adjustable within narrow limits, so that the possesser may not only correct any error of setting on the part of the maker, but may readj ust the blade if disturbed in position by any accident; and it therefore consists in two eccentric or cam screws pass ing through the stock and applied to bear against nthe edge of the blade or toward each side of the pivot-pin, upon which said blade may move, so that by properly turning said eccentrics, the blade may be caused slightly to change its angle in respect to the stock.

That others may fully understand my'invention I will particularly describe it.

A is the stock of an ordinary try-square, and B is the blade of the same, which is required to be set accurately at right angles to said stock. b b are the twoordinary fastening pins,some times rivets,but generally screws. l

The pin b' forms a pivot upon which the blade B may move, and the pin b', therefore, is provided with a slightly elongated hole or slot, so that said pin b serves as a re-enforce for the stock, but does not hold the blade in position.

Immediately below the edge of the blade B,

I insert two pins or screws C O, through the stock, and that part of each of said pins which comes opposite `the edgeof the blade I make eccentric, as shown in Fig. 3. When the blade is in place, and the pin b and eccentrics G C, are in their seats, then said blade will have three points of support, and the turning around of said eccentrics will shift the relative positions of said points, and cause" the blade to be correspondingly shifted; and it will thus be an easy matter for any skilful person to bring his try-square to a perfect ad-f justment. y

It is obvious that the eccentrics G 0,'may

be placed through holes made in the blade B,

CHARLES A. scHAEFEn.

Witness-es WILLIAM WOLF, HENRY FLEIscHIIAUER. 

